Radeon HD 4650 512MB vs Radeon HD 7790

Intro

Compare all of that to the Radeon HD 7790, which has a GPU core clock speed of 1000 MHz, and 1024 MB of GDDR5 RAM running at 1500 MHz through a 128-bit bus. It also features 896 SPUs, 56 Texture Address Units, and 16 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 7790		85 Watts
	Difference: 30 Watts (55%)

Memory Bandwidth

Theoretically, the Radeon HD 7790 should be a lot faster than the Radeon HD 4650 512MB overall. (explain)

Radeon HD 7790		96000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 80000 (500%)

Texel Rate

The Radeon HD 7790 will be a lot (about 192%) more effective at anisotropic filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 7790		56000 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 36800 (192%)

Pixel Rate

The Radeon HD 7790 will be quite a bit (approximately 233%) better at anti-aliasing than the Radeon HD 4650 512MB, and also will be capable of handling higher resolutions more effectively. (explain)

Radeon HD 7790		16000 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 11200 (233%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of data (measured in megabytes per second) that can be transferred past the external memory interface in one second. The number is calculated by multiplying the interface width by its memory clock speed. If it uses DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This figure is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.